Mobility and Cooperation: On the Run

In public goods experiments where subjects may change groups, we observe a continual flight of the more cooperative subjects away from the less cooperative ones. The less cooperative subjects attempt to enter cooperative groups in order to free-ride on their contributions. Lorsque les sujets peuvent changer de groupes dans les expériences sur les contributions volontaires aux biens publics, nous observons que les sujets plus coopératifs délaissent les sujets moins coopératifs. De plus, ces derniers essaient de joindre les groupes coopératifs pour profiter comme resquilleurs de leurs contributions.Public goods, Tiebout hypothesis, migration, experimental economics, Biens publics, hypothèse de Tiebout, migration, économie expérimentale

Conventions and Local Interaction Structures: Experimental Evidence

We present a set of experimental coordination games with a payoff-dominant and a risk-dominant Nash equilibrium. We examine how much local interaction structures affect players' strategy choices. Our three major observations are the following: First, local interaction with open neighborhoods along a circle leads to less coordination on the payoff-dominant equilibrium than interaction in closed neighborhoods (see also Keser, Ehrhart, and Berninghaus, Economics Letters, 1998). Second, when players are allocated around a circle, the neighborhood size has, in the long run, no effect on the players' strategy choices. Third, with the same neighborhood size, players allocated on a lattice tend less than players allocated around a circle to coordinate on the payoff-dominant equilibrium. This is true although the players are given exactly the same instructions. Nous présentons une série de jeux de coordination expérimentaux avec un équilibre de Nash qui est dominant par rapport au risque et un autre équilibre qui est dominant par rapport au gain. Nous examinons à quel degré des structures d'interaction locale ont une influence sur les choix de stratégies. Nos observations majeures sont les suivantes: Premièrement, l'interaction locale avec des voisinages autour d'un cercle implique moins de coordination sur l'équilibre qui est dominant par rapport au gain que l'interaction dans des voisinages fermés (voir aussi Keser, Ehrhart et Berninghaus, Economics Letters, 1998). Deuxièmement, quand les joueurs sont disposés en cercle, la taille du voisinage n'a pas d'effet à long terme sur les choix de stratégie par les joueurs. Troisièmement, avec la même taille de voisinage, des joueurs disposés en tore tendent moins que des joueurs disposés en cercle de se coordonner sur l'équilibre qui est dominant par rapport au gain. Cette différence est présente bien que les joueurs reçoivent exactement les mêmes instructions.Equilibrium selection, local interaction structures, experimental economics, Sélection des équilibres, structure d'interaction locale, économie expérimentale

Budget processes: Theory and experimental evidence

This paper studies budget processes, both theoretically and experimentally. We compare the outcomes of bottom-up and top-down budget processes. It is often presumed that a top-down budget process leads to a smaller overall budget than a bottom-up budget process. We show, using structurally induced equilibrium theory, that this may but need not be the case. To test the implications for budget processes of structurally induced equilibrium theory, we conduct a series of experiments. The evidence from these experiments supports the predictions of structurally induced equilibrium theory, both at the aggregate and at the individual subject level. --

Budget Processes: Theory and Experimental Evidence

This paper studies budget processes, both theoretically and experimentally. We give a sufficient condition for top-down and bottom-up budget processes to have the same voting equilibrium. Furthermore, at a voting equilibrium, it is not always true, as often presumed, that a top-down budget process leads to a smaller overall budget than does a bottom-up budget process. To test the implications for budget processes of voting equilibrium theory, we conduct a series of 128 voting experiments using subjects in a behavior laboratory. The experimental evidence from these experiments is well organized by voting equilibrium theory, both at the aggregate level and at the individual subject level. In particular, subjects display considerable evidence of rationality in their proposals and votes. More complete information and fewer spending categories lead to greater predictive success of voting equilibrium theory, and reduce the time needed to reach a budget decision. Ce texte étudie des processus de construction budgétaire, tant d'un point de vue théorique que d'un point de vue de leur application expérimentale. Nous spécifions une condition suffisante afin que l'équilibre électoral soit le même pour les processus de construction budgétaire qu'ils soient de type top-down (par le haut) ou de type bottom-up (par le bas). D'autre part, et bien que cela soit souvent supposé, il n'est pas toujours vrai qu'à l'équilibre électoral un processus de construction budgétaire top-down conduise à un plus faible budget global que ne le ferait un processus budgétaire de type bottom-up. Pour tester les conséquences de la théorie de l'équilibre électoral sur les processus de construction budgétaire, une série de 128 expériences a été conduite en laboratoire. Les résultats de ces expériences sont largement conformes à la théorie de l'équilibre électoral, aussi bien au niveau des donnés agrégés qu'au niveau des résultats individuels. Plus particulièrement, l'étude des résultats révèle que les joueurs font preuve d'une véritable rationalité de décision tant pour formuler leur proposition que pour établir leur stratégie de vote. Enfin, une information plus complète et moins de catégories de dépenses conduisent à un plus grand succès de prévision de la théorie de l'équilibre électoral et réduisent le temps nécessaire pour atteindre une ratification budgétaire.Budget processes, voting equilibrium, experimental economics, Processus de construction budgétaire, équilibre électoral, économie expérimentale

Budget Processes: Theory and Experimental Evidence

This paper studies budget processes, both theoretically and experimentally. We compare the outcomes of bottom-up and top-down budget processes. It is often presumed that a top-down budget process leads to a smaller overall budget than a bottom-up budget process. Ferejohn and Krehbiel (1987) showed theoretically that this need not be the case. We test experimentally the theoretical predictions of their work. The evidence from these experiments lends strong support to their theory, both at the aggregate and the individual subject level.Budget processes; voting equilibrium; experimental economics

Budget Processes: Theory and Experimental Evidence

This paper studies budget processes, both theoretically and experimentally. We compare the outcomes of bottom-up and top-down budget processes. It is often presumed that a top-down budget process leads to a smaller overall budget than a bottom-up budget process. Ferejohn and Krehbiel (1987) showed theoretically that this need not be the case. We test experimentally the theoretical predictions of their work. The evidence from these experiments lends strong support to their theory, both at the aggregate and the individual subject level.budget processes, voting equilibrium, experimental economics

Complex organic molecules in the interstellar medium: IRAM 30 m line survey of Sagittarius B2(N) and (M)

The discovery of amino acids in meteorites and the detection of glycine in samples returned from a comet to Earth suggest that the interstellar chemistry is capable of producing such complex organic molecules. Our goal is to investigate the degree of chemical complexity that can be reached in the ISM. We performed an unbiased, spectral line survey toward Sgr B2(N) and (M) with the IRAM 30m telescope in the 3mm window. The spectra were analyzed with a simple radiative transfer model that assumes LTE but takes optical depth effects into account. About 3675 and 945 spectral lines with a peak signal-to-noise ratio higher than 4 are detected toward N and M, i.e. about 102 and 26 lines per GHz, respectively. This represents an increase by about a factor of 2 over previous surveys of Sgr B2. About 70% and 47% of the lines detected toward N and M are identified and assigned to 56 and 46 distinct molecules as well as to 66 and 54 less abundant isotopologues of these molecules, respectively. We also report the detection of transitions from 59 and 24 catalog entries corresponding to vibrationally or torsionally excited states of some of these molecules, respectively. Excitation temperatures and column densities were derived for each species but should be used with caution. Among the detected molecules, aminoacetonitrile, n-propyl cyanide, and ethyl formate were reported for the first time in space based on this survey, as were 5 rare isotopologues of vinyl cyanide, cyanoacetylene, and hydrogen cyanide. We also report the detection of transitions from within 12 new vib. or tors. excited states of known molecules. Although the large number of unidentified lines may still allow future identification of new molecules, we expect most of these lines to belong to vib. or tors. excited states or to rare isotopologues of known molecules for which spectroscopic predictions are currently missing. (abridged)Comment: Accepted for publication in A&A. 266 pages (39 pages of text), 111 tables, 8 figure

Angular momentum evolution of bulge stars in disc galaxies in NIHAO

We study the origin of bulge stars and their angular momentum (AM) evolution in 10 spiral galaxies with baryonic masses above $10^{10}$M$_\odot$ in the NIHAO galaxy formation simulations. The simulated galaxies are in good agreement with observations of the relation between specific AM and mass of the baryonic component and the stellar bulge-to-total ratio ($B/T$). We divide the star particles at $z=0$ into disc and bulge components using a hybrid photometric/kinematic decomposition method that identifies all central mass above an exponential disc profile as the `bulge'. By tracking the bulge star particles back in time, we find that on average 95\% of the bulge stars formed {\it in situ}, 3\% formed {\it ex situ} in satellites of the same halo, and only 2\% formed {\it ex situ} in external galaxies. The evolution of the AM distribution of the bulge stars paints an interesting picture: the higher the final $B/T$ ratio, the more the specific AM remains preserved during the bulge formation. In all cases, bulge stars migrate significantly towards the central region, reducing their average galactocentric radius by roughly a factor 2, independently of the final $B/T$ value. However, in the higher $B/T$ ($\gtrsim0.2$) objects, the velocity of the bulge stars increases and the AM of the bulge is almost conserved, whereas at lower $B/T$ values, the velocity of the bulge stars decreases and the AM of bulge reduces. The correlation between the evolution of the AM and $B/T$ suggests that bulge and disc formation are closely linked and cannot be treated as independent processes.Comment: 17 pages, 16 Figures, 1 table; accepted for publication in MNRA

Small intestinal volvulus in 47 cows

OBJECTIVE: To describe the findings, treatment, and outcome of small intestinal volvulus (SIV) in 47 cows. ANIMALS AND PROCEDURE: Retrospective analysis of medical records. Comparison of the findings for 18 surviving and 29 non-surviving cows. RESULTS: The most common abnormal vital signs were tachycardia (68.0%), tachypnea (59.6%), and decreased rectal temperature (51.1%). Signs of colic occurred in 66.0% of cows in the study. Rumen motility was reduced or absent in 93.6% of cows, and intestinal motility in 76.6%. Clinical signs on ballottement and/or percussion and simultaneous auscultation were positive on the right side in 78.7% of cows. Transrectal examination showed dilated small intestines in 48.9% of cows. The rectum contained little or no feces in 93.6% of cows. The principal laboratory abnormalities were hypocalcemia (74.1%), hypokalemia (73.8%), azotemia (62.8%), hypermagnesemia (61.6%), and hemoconcentration (60.0%). The principal ultrasonographic findings were dilated small intestines (87.1%) and reduced or absent small intestinal motility (85.2%). Forty-one of the 47 cows underwent right flank laparotomy and the SIV was reduced in 21 cows. When comparing the clinical and laboratory findings of 18 surviving and 29 non-surviving cows, the groups differed significantly with respect to severely abnormal general condition (16.7 versus 37.9%), rumen stasis (22.2 versus 79.3%), intestinal atony (16.7 versus 48.3%), serum urea concentration (6.5 versus 9.8 mmol/L), and serum magnesium concentration (0.98 versus 1.30 mmol/L). In summary, 38.3% of the cows were discharged and 61.7% were euthanized before, during, or after surgery. CONCLUSION AND CLINICAL RELEVANCE: An acute course of disease, little or no feces in the rectum, and dilated small intestines were characteristic of SIV in this study population